Filament-support.



W. R. BURROWS.

FILAMBNT SUPPORT.

APPLIOATION FILED MAB.13.1907.

1,013,859. Patented @11.9, 1912.

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WILLIAM R. BURBOWS, OF NEWARK, NEW JERSEY, ASSIGNOR T0 GENERAL COMPANY, A CORPORATION 0F NEW YORK.

FILAMENT-SUPPORT.

Specification of Letters Patent. Application med March 1s, 1907. serial No. 362,175.

Patented aan. e, i912.

To all whom it may concern:

Be it known that I, WILLIAM R. BURRows, a citizen of the United States, residing at Newark, county of Essex, State of New Jersey, have invented certain new and useful Improvements in Filament- Supports, of which the following is a specification.

My present invention relates to incandescent lamps, and more particularly to means for supporting the iilamentstherein.

Incandescent lamps having filaments of tungsten, osmium, molybdenum, and other` refractory metals, must be provided with some means for holding the filaments in position. These metals, for instance tungsten, operate at very high temperatures, and the supporting means must be of such a nature that the part contacting with the lfilament will not alloy or chemically combine therewith. Furthermore, thesupporting means should permit the progressive contraction of the filament during normal operation of the lamp. This progressive contraction is ordinarily suiiicient to rup-. ture the filament if rigidly anchored at each end, even though the filament may have been originally adjusted with suicient slack to permit of the normal expansion and contraction due to changes in temperature.-

The filament support embodied in my present invention is so constituted that it does not chemically combine with the fila- I ment, and is so arranged that it will maintain the ilament under tension when the lamp is new without danger of subjecting the filament to a disruptive tension after the laments have aged and shrunk.

My improved filament support has the additional advantage of protecting the filaments from shocks and jars during transportation. When the filaments consist of tungsten, or other nonductile material, this last mentioned characteristic is of very considerable importance.

The drawings forming a part of this specification show my invention as applied to a four filament lamp.

The lamp` bulb 1 is of ordinary type and provided with the usual stem 2 through which the leading-in conductors pass. The stem is provided with a glass pedestal 3 having a glass hub 4 near its base, and a cross-bar 5 at its top. Platinum or other metal holders 6 are sc a'led in the hub 4 and serve to connect the adjacent ends of lthe filament loops 7,8 and J9 and 10. lThese platinum wires may bewelded or otherwise attached to the ends of the filaments. The

radial arms, but the arms are so sealed in the glass that they do not contact with each other or with the coiled spring. The radial arms may be made of copper as I find that copper does not readily alloy or combine with incandescent tungsten. The large diameter of the wire prevents the copper from heating to its fusing temperature. If preferred, a more refractory material than coppr may be employed, as tantalum or the It will be noted that as the filaments contract, they put the radial arms under a transverse stress and cause the compression and transverse fleXure of the helical springs 11 and 12. It is possible to secure a very considerable movement of the end of the radial arm without materially increasing the tension on the filament. The flexibility of the supporting means permits .progressive contraction of the filaments during normal life of the lam but maintains the proper tension on the lament, both when hot and when cold. The peculiar arrangement of the springs protects the more fragile filaments from jars and shocks during trans'- portation.

What I claim as new and desire to secure by Letters Patent of the United States, 1s,- f

1. The combination of avlamp stem having a central pedestal, a coiled spring supported thereby and havingits axis parallel with that of the pedestal, laterally extend ing arms supported by said spring, and filament loops engaging with said radial arms,

the portion of an arm engaging with a iilament undergoing displacement with reference to a plane perpendicular to the fila ment loop as the longitudinal direction of c the loop varies in length while the portion adjacent the spring remains'relatively stationary.

2. The combination 'of a lamp filament, a supporting arm engaging therewith, and a coiled spring attached. to said arm and subjected to. compression and transverse iexure when said filament contracts.

3. The combination of a filament loop,

a coiled helical spring having its axis substantially -parallel to that of the loop, and

a laterally extending arm supported by said spring engaging with said l filament loop and free to tilt with reference to said axis.

4. The'combination of a` lamp stem, a

pedestal carried thereon, a spring mounted filaments disposed about said pedestal, a

springcarried by said pedestal, and means for supporting lsaid filaments comprising a plurality of suitably rigid devices carried by said spring and movable laterally with reference to said pedestal.

6..The combination of a filament loop, a supporting arm engaging the bend'of said loop and extending transversely ence thereto, and a springsupporting said arm and extending transversely with reference to the same -which is subject to trans- .verse iiexure when the ilament varies in 7. The combination with a lurality of filaments and `a relatively rigi supporting member adjacent the same of a device adapted to yaiiord the filaments resilient support comprising rigid means directly supporting said filaments and extending transversely with reference theretoy and a spring part 'extending transversely with reference to said means by which said means is carried from said member, said spring part being subject to transverse {iexure when a filament contracts.

In witness whereof, I have hereunto set my hand this `Sth day of March, 1907.

` WILLIAM R. BURROWS. 'f

with refer- 

